Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Allowance for loan losses:
Beginning balance	$ 15,821	$ 15,767
Provision for loan losses	0	0
Charge-offs	(9)	0
Recoveries	5	4
Ending balance	15,817	15,771
Ending ALLL related to loans collectively evaluated for impairment	15,113		$ 15,043
Ending ALLL related to loans individually evaluated for impairment	704		778
Ending ALLL	15,817		15,821
Collectively evaluated for impairment	1,755,697		1,746,714
Individually evaluated for impairment	14,743		15,038
Total loans	$ 1,772,538		$ 1,763,864
Ratio of allowance for loan losses to total loans	0.89%		0.90%
Allowance for loan losses to non-accrual loans	2200.00%		2270.00%
Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	2,098		2,112
Commercial loans \| Commercial and industrial
Allowance for loan losses:
Beginning balance	2,436	3,654
Provision for loan losses	180	35
Charge-offs	(9)	0
Recoveries	5	4
Ending balance	2,612	3,693
Ending ALLL related to loans collectively evaluated for impairment	2,188		1,970
Ending ALLL related to loans individually evaluated for impairment	424		466
Ending ALLL	2,612		2,436
Collectively evaluated for impairment	236,113		228,883
Individually evaluated for impairment	1,507		1,825
Total loans	$ 237,646		$ 230,739
Ratio of allowance for loan losses to total loans	1.10%		1.06%
Allowance for loan losses to non-accrual loans	845.00%
Commercial loans \| Commercial and industrial \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	26		31
Commercial real estate loans \| Commercial real estate, owner-occupied
Allowance for loan losses:
Beginning balance	2,407	2,294
Provision for loan losses	(49)	(214)
Charge-offs	0	0
Recoveries	0	0
Ending balance	2,358	2,080
Ending ALLL related to loans collectively evaluated for impairment	2,197		2,218
Ending ALLL related to loans individually evaluated for impairment	161		189
Ending ALLL	2,358		2,407
Collectively evaluated for impairment	302,411		305,097
Individually evaluated for impairment	7,001		6,993
Total loans	$ 310,588		$ 313,277
Ratio of allowance for loan losses to total loans	0.76%		0.77%
Commercial real estate loans \| Commercial real estate, owner-occupied \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	1,176		1,187
Commercial real estate loans \| Commercial real estate, investor
Allowance for loan losses:
Beginning balance	7,703	6,475
Provision for loan losses	63	(20)
Charge-offs	0	0
Recoveries	0	0
Ending balance	7,766	6,455
Ending ALLL related to loans collectively evaluated for impairment	7,719		7,658
Ending ALLL related to loans individually evaluated for impairment	47		45
Ending ALLL	7,766		7,703
Collectively evaluated for impairment	875,866		870,778
Individually evaluated for impairment	1,812		1,821
Total loans	$ 878,494		$ 873,410
Ratio of allowance for loan losses to total loans	0.88%		0.88%
Commercial real estate loans \| Commercial real estate, investor \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	816		811
Commercial real estate loans \| Construction
Allowance for loan losses:
Beginning balance	756	681
Provision for loan losses	(52)	16
Charge-offs	0	0
Recoveries	0	0
Ending balance	704	697
Ending ALLL related to loans collectively evaluated for impairment	704		756
Ending ALLL related to loans individually evaluated for impairment	0		0
Ending ALLL	704		756
Collectively evaluated for impairment	69,580		73,735
Individually evaluated for impairment	2,691		2,688
Total loans	$ 72,271		$ 76,423
Ratio of allowance for loan losses to total loans	0.97%		0.99%
Commercial real estate loans \| Construction \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	0		0
Residential loans \| Home equity
Allowance for loan losses:
Beginning balance	915	1,031
Provision for loan losses	8	(52)
Charge-offs	0	0
Recoveries	0	0
Ending balance	923	979
Ending ALLL related to loans collectively evaluated for impairment	918		910
Ending ALLL related to loans individually evaluated for impairment	5		5
Ending ALLL	923		915
Collectively evaluated for impairment	123,835		124,049
Individually evaluated for impairment	597		564
Total loans	$ 124,512		$ 124,696
Ratio of allowance for loan losses to total loans	0.74%		0.73%
Allowance for loan losses to non-accrual loans	267.00%		292.00%
Residential loans \| Home equity \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	80		83
Residential loans \| Other residential
Allowance for loan losses:
Beginning balance	800	536
Provision for loan losses	0	7
Charge-offs	0	0
Recoveries	0	0
Ending balance	800	543
Ending ALLL related to loans collectively evaluated for impairment	800		800
Ending ALLL related to loans individually evaluated for impairment	0		0
Ending ALLL	800		800
Collectively evaluated for impairment	117,098		117,385
Individually evaluated for impairment	460		462
Total loans	$ 117,558		$ 117,847
Ratio of allowance for loan losses to total loans	0.68%		0.68%
Residential loans \| Other residential \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	0		0
Consumer loans \| Installment and other consumer
Allowance for loan losses:
Beginning balance	310	378
Provision for loan losses	30	(27)
Charge-offs	0	0
Recoveries	0	0
Ending balance	340	351
Ending ALLL related to loans collectively evaluated for impairment	273		237
Ending ALLL related to loans individually evaluated for impairment	67		73
Ending ALLL	340		310
Collectively evaluated for impairment	30,794		26,787
Individually evaluated for impairment	675		685
Total loans	$ 31,469		$ 27,472
Ratio of allowance for loan losses to total loans	1.08%		1.13%
Allowance for loan losses to non-accrual loans	531.00%
Consumer loans \| Installment and other consumer \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	$ 0		$ 0
Purchased credit-impaired	0		0
Unallocated
Allowance for loan losses:
Beginning balance	494	718
Provision for loan losses	(180)	255
Charge-offs	0	0
Recoveries	0	0
Ending balance	314	$ 973
Ending ALLL related to loans collectively evaluated for impairment	314		494
Ending ALLL related to loans individually evaluated for impairment	0		0
Ending ALLL	314		494
Collectively evaluated for impairment	0		0
Individually evaluated for impairment	0		0
Total loans	0		0
Unallocated \| Purchased credit-impaired
Allowance for loan losses:
Ending ALLL	0		0
Purchased credit-impaired	$ 0		$ 0

Allowance as percentage of non-accrual loans.

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Allowance as percentage of total loans.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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A valuation allowance for financing receivables that are expected to be uncollectible.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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